EC 18.104.22.168 Enzyme
biotin-dependent malonate decarboxylase;
malonate decarboxylase (with biotin);
malonate decarboxylase (ambiguous)
Catalysing the translocation of inorganic cations;
Linked to decarboxylation
malonate carboxy-lyase (biotin-dependent)
malonate + H+ + Na+ [side 1] = acetate + CO2 + Na+ [side 2]
Na+ [side 1]
Na+ [side 2]
Two types of malonate decarboxylase are currently known, both of which form multienzyme complexes. The enzyme described here is a membrane-bound biotin-dependent, Na+-translocating enzyme . The other type is a biotin-independent cytosolic protein (cf. EC
, biotin-independent malonate decarboxylase). As free malonate is chemically rather inert, it has to be activated prior to decarboxylation. Both enzymes achieve this by exchanging malonate with an acetyl group bound to an acyl-carrier protiein (ACP), to form malonyl-ACP and acetate, with subsequent decarboxylation regenerating the acetyl-bound form of the enzyme. The ACP subunit of both enzymes differs from that found in fatty-acid biosynthesis by having phosphopantethine attached to a serine side-chain as 2-(5-triphosphoribosyl)-3-dephospho-CoA rather than as phosphopantetheine 4'-phosphate. In the anaerobic bacterium Malonomonas rubra, the components of the multienzyme complex/enzymes involved in carrying out the reactions of this enzyme are as follows: MadA (EC
, acetyl-S-ACP:malonate ACP transferase), MadB (EC
, carboxybiotin decarboxylase), MadC/MadD (EC
, malonyl-S-ACP:biotin-protein carboxyltransferase) and MadH (EC
, acetate--[acyl-carrier protein] ligase). Two other components that are involved are MadE, the acyl-carrier protein and MadF, the biotin protein. The carboxy group is lost with retention of configuration .
EC 22.214.171.124 created 2008 as EC 126.96.36.199, transferred 2018 to EC 188.8.131.52
Hilbi H, Dehning I, Schink B, Dimroth P
Malonate decarboxylase of Malonomonas rubra, a novel type of biotin-containing acetyl enzyme.
Eur J Biochem 207:117-23 (1992)
Hilbi H, Dimroth P
Purification and characterization of a cytoplasmic enzyme component of the Na+-activated malonate decarboxylase system of Malonomonas rubra: acetyl-S-acyl carrier protein: malonate acyl carrier protein-SH transferase.
Arch Microbiol 162:48-56 (1994)
Berg M, Hilbi H, Dimroth P
The acyl carrier protein of malonate decarboxylase of Malonomonas rubra contains 2'-(5"-phosphoribosyl)-3'-dephosphocoenzyme A as a prosthetic group.
Biochemistry 35:4689-96 (1996)
Berg M, Hilbi H, Dimroth P
Sequence of a gene cluster from Malonomonas rubra encoding components of the malonate decarboxylase Na+ pump and evidence for their function.
Eur J Biochem 245:103-15 (1997)
Micklefield, J., Harris, K.J., Groger, S., Mocek, U., Hilbi, H., Dimroth, P. and Floss, H.G.
Stereochemical course of malonate decarboxylase in Malonomonas rubra has biotin decarboxylation with retention.
J Am Chem Soc 117:1153-1154 (1995)
Malonate metabolism: biochemistry, molecular biology, physiology, and industrial application.
J Biochem Mol Biol 35:443-51 (2002)
Dimroth P, Hilbi H
Enzymic and genetic basis for bacterial growth on malonate.
Mol Microbiol 25:3-10 (1997)
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